Add viewer-range categories, nomination tracking, dynamic showact form, session timeout, share URLs, and workflow-per-season

Features:
- Category viewer ranges + subcategory templates (admin group modal, tree workspace)
- Nomination enrichment via TwitchTracker API (NominationEnrichmentService,
  TwitchTrackerViewerStatsProvider) with admin tracking rules editor
- Nomination group tracker: CategoryGroupName as primary identifier,
  CategoryId stays as nullable legacy field; StreamerIdentity table
- Dynamic showact application form builder (AdminShowactFormBuilder,
  ShowactApplicationSchedule)
- Session idle timeout setting (AdminSessionTimeoutCard)
- Share URLs for X and Discord (SiteSettings, public extras)
- Workflow rules now stored per season (falls back to global SiteSettings)
- New admin routes: settings/access, settings/workflows, tracking-rules
- New admin review workspace with subcategory tabs
- AdminCategoriesView rebuilt with group/subcategory modals

Migrations (all additive):
- AddShareUrls, AddShowactDynamicForm, AddCategoryViewerRanges,
  AddSessionIdleTimeoutSettings, AddSeasonSubcategoryTemplates,
  AddNominationGroupTrackerIdentity, AddShowactApplicationSchedule,
  AddSeasonWorkflowRulesJson

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/admin/AdminReviewSubcategoryTabs.vue

@@ -0,0 +1,43 @@
+<script setup lang="ts">
+defineProps<{
+  tabs: Array<{ id: number | null; label: string; count: number; note?: string }>
+  modelValue: number | null
+}>()
+
+const emit = defineEmits<{
+  'update:modelValue': [value: number | null]
+}>()
+</script>
+
+<template>
+  <div class="rounded-[24px] border border-violet-100 bg-[linear-gradient(180deg,#fcfaff_0%,#f8f4ff_100%)] p-4">
+    <div>
+      <p class="text-[11px] font-semibold uppercase tracking-[0.2em] text-violet-500">Unterkategorien</p>
+      <p class="mt-1 text-sm text-slate-500">Nur die aktuell gewählte Tier-Stufe wird in der Queue gezeigt.</p>
+    </div>
+
+    <div class="mt-4 grid gap-2 sm:grid-cols-2 xl:grid-cols-4">
+      <button
+        v-for="tab in tabs"
+        :key="tab.id ?? 'all'"
+        type="button"
+        class="rounded-[20px] border px-4 py-3 text-left transition"
+        :class="modelValue === tab.id ? 'border-violet-300 bg-white text-violet-900 shadow-[0_12px_28px_rgba(168,145,214,0.14)] ring-2 ring-violet-100' : 'border-violet-100 bg-white/75 text-slate-600 hover:border-violet-200 hover:bg-white'"
+        @click="emit('update:modelValue', tab.id)"
+      >
+        <span class="flex items-start justify-between gap-3">
+          <span class="min-w-0">
+            <span class="block text-sm font-semibold">{{ tab.label }}</span>
+            <span v-if="tab.note" class="mt-1 block text-[11px] font-medium text-slate-500">{{ tab.note }}</span>
+          </span>
+          <span
+            class="inline-flex min-h-8 min-w-8 items-center justify-center rounded-full border px-2 text-xs font-bold"
+            :class="modelValue === tab.id ? 'border-violet-200 bg-violet-100 text-violet-800' : 'border-violet-100 bg-violet-50 text-violet-700'"
+          >
+            {{ tab.count }}
+          </span>
+        </span>
+      </button>
+    </div>
+  </div>
+</template>